The Role of Opioid in the Mechanism of the Hypotensive Effect by Simulating Acupuncture on Rat Hindlimb

The present study investigated the role of central opioid in the hypotensive effect of somatic afferent inputs. The femoral arterial pressure and electrocardiogram (ECG) of rats were recorded when the hypothalamic paraventricular nucleus (the PVN) was electrically stimulated or chemically activated (microinjection of L-glutamate) with or without microinjection of naloxone into the lateral ventricle of brain. Stimulation of the deep peroneal nerve (the DPN) decreased the pressor response elicited by electrical stimulation or chemical activation of the PVN. This inhibitory effect was reduced by microinjection of naloxone into the lateral ventricle of brain. These data suggest that opioid receptor in brain is involved in the inhibitory effect of stimulating the DPN on the pressor response induced by activation of the PVN.